Circuit interrupter



July 30, 1963 J. L. RlDlNGS 3,099,733

CIRCUIT INTERRUPTER Filed Nov. 19, 1959 5 Sheets-Sheet 1 Fig. l

f/ y} James L. Ridings ATTORNEY y 1963 J. L. RIDINGS CIRCUIT INTERRUPTER 3 Sheets-Sheet 2 Filed NOV. 19, 1959 July 30, 1963 J. L. RIDINGS 3,099,733

CIRCUIT INTERRUPTER Filed Nov. 19, 1959 v 3 Sheets-Sheet 3 Fig. 7

United States Patent 3,099,733 CIRCUIT INTERRUPTER James L. Ridings, Lima, ()hio, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., :1 corporation of Pennsylvania Filed Nov. 19, 1959, Ser. No. 854,127 13 Claims. (Cl. 260-145) a plurality of serially related arc-extinguishing units supported within a grounded exhaust tank by a pair of terminal bushings extending into said tank. A high-pressure tank, at line potential and containing a supply of fluid under high pressure, is supported within the exhaust tank, and has associated therewith a single blast valve for directing a single blast of fluid through a plurality of conduits of different lengths to extinguish a plurality of arcs. This present invention is an improvement over the aforesaid application.

It is an object of this invention to provide an improved fluidablast circuit interrupter embodying a high-pressure tank external to the exhaust tank and at ground potential to eliminate piping and shielding within the exhaust tank and to provide for easier inspection and maintenance.

Another object is to provide improved arc-extinguishing means for a multi-break fluid-blast circuit interrupter with means for simultaneously operating a plurality of separate blast valves to direct a separate blast of gas at each of a plurality of serially related sets of relatively movable contacts. This enables more accurate unittesting in the high-power laboratory as two of the blasts valves and their associated sets of contacts can be rendered inoperative with the contacts in a closed position, and accurate predictions of operation of the complete circuit interrupter can be made from the test results of the operation of one blast-valve and its associated arcextinguishing unit.

Another object is to provide an improved multi-break fluid-blast circuit interrupter with a plurality of simultaneously operated blast valves equidistant from the contact breaks. This assures that the separate blasts of fluid will be of equal force, and that they will simultaneously reach their associated arc-extinguishing units.

Another object is to provide improved cross-blast arcextinguishing means for a 'multi-break fluid-blast circuit interrupter.

A more general object is to provide an improved circnit interrupter which will be adaptable for performing more effectively over wider voltage and current ranges than circuit interrupters heretofore used in the industry.

Further objects and advantages will readily become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

FIG. 1 is a perspective view of a three-pole fluid-blast circuit interrupter embodying the features of the present invention;

FIG. 2 is an enlarged, fragmentary, vertical view, partly in section, of one of the poles of the three-pole circuit interrupter shown in FIG. 1, with the pole structure being shown reversed from the position illustrated in FIG. 1;

FIG. 3 is an enlarged, fragmentary view, partly in section, illustrating one of the arc-extinguishing units and blast valves of the invention;

FIG. 4 is a sectional view taken substantially along 3,099,733 Patented July 30, 1963 line lVIV of FIG. 3, the movable contact assemblage being left out for purposes of clarity;

FIG. 5 is a sectional view taken along line VV of FIG. 3 showing the movable contact assemblage, the parts in the background being omitted for clarity;

FIG. 6 is a top plan view of the arc splitter box of FIG. 4; and,

FIG. 7 is an enlarged View illustrating how the arc is forced between the arc splitter plates to be broken up.

Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral 1 generally designates a high-voltage, high-power, fluid-blast circuit interrupter adaptable for the control of a three-phase transmission circuit, the lines of which are indicated by the reference characters L L L L L and L An elongated exhaust tank 3 is provided for each of the pole-units A, B and C of the circuit interrupter 1. With reference to FIG. 2, there are three blast valve casings 5 supported lengthwise along the bottom of each exhaust tank 3. Each of the three sets of blast valve casings 5 support a high-pressure tank 7 and also interconnects the high-pressure tank 7 with its associated exhaust tank 3. A weatherproof enclosing tube 9 encloses a rotatable operating rod 11 (FIG. 2), which mechanically interconnects the three-pole units A, B and C for simultaneous operation. A blast-valve rod 14 for each pole-unit is mechanically connected to the operating rod 11.

With further reference to FIG. 1, a mechanism and gas-control housing 15 is disposed adjacent the front poleunit A. The mechanism housing 15 encloses a conventional pneumatic mechanism for effecting rotation of the operating rod 11, and it also encloses the equipment for reconditioning the dual-pressure gas supply. Any suitable operating mechanism may be employed, such as hydraulic, solenoid-operated, or pneumatic, as mentioned.

Each of the exhaust-tank structures 3 includes a generally horizontally extending, cylindrical tank portion 17, which has hinged closure caps 19 at opposite ends thereof. Each of the closure caps 19 may be swung to an open position to permit the lateral withdrawal of an arc-extinguishing assemblage 21' (FIG. 2) from the exhaust tank 3 for maintenance purposes.

Each of the exhaust tanks 3 is supported by two flange plates 25, which are welded to two steel beams 27 that extend beneath all three of the pole-units A, B and C. Thus, a crane may be employed to bodily lift the pair of steel beams 27, together with the several pole-units A, B and C, and the housing .15, to permit the bodily placement of the circuit interrupter 1 upon a mounting slab of concrete, or the like, as is well known by those skilled in the art.

FIG. 1 also shows a pair of upstanding cylindrical steel positioning supports 29, disposed adjacent opposite ends of each tank portion 17, to permit the mounting therewithin of a pair of terminal bushings, indicated generally at 12 and 13. The longitudinally extending multi-break arc-extingishing assemblage 21 is detachably secured at its ends to the lower internal ends 12A and 13A (FIG. 2) respectively of the pair of terminal bushings 12 and 13. As pointed out hereinbefore, the pole-unit A illustrated in FIG. 2 is reversed from the position in which it is shown in FIG. 1.

A through-type current transformer 31 encircles each of the terminal bushings 12, '13 of FIG. 1 to provide relaying protection as is well known in the art. There is sufiicient clearance between the inner diameter of each of the current transformers 31 and the weather sheds 12B, 13B so that the current transformers 31 may be easily placed in position over the terminal bushings 12, 13.

The pole-units A, B and C, are of identical construction, and, therefore, only the pole-unit A will be specifi- 3 cally described, it being understood that the description applies also to the pole-units B and C.

Referring to FIG. 2, it will be observed that the longitudinally extending, multi-break arc-extinguishing assemblage 21 extends substantially coaxially along the center of the exhaust tank 3. Generally, the multi-break arcextingnishing assemblage 21 includes three similar serially related arc-extinguishing units 33, -35 and 37, each of which includes a stationary contact structure 39, a movable contact 41 and an arc splitter box 43 (FIG. '3).

The stationary contact structures '39 form part of a ladder-shaped structure including a pair of longitudinally extending insulating rods 45, which are attached at opposite ends thereof to end castings 4'7, 49 (FIG. 2), that are supported by the interior ends 12A and 13A, respectively, of the terminal bushings 112 and 13. Three generally cup-shaped members 51 are attached between the insulating rods 45 forming generally three rungs of a ladder-shaped structure, as illustrated in FIGS. 3 and 4. A relatively stationary rod-shaped arcing contact 53 (FIG. 3) and a cluster of resilient main spring contact fingers 55 are mounted within each of the relatively stationary cup-shaped members 51 to form part of each stationary contact structure 39.

The three movable contacts 41, associated with the three arc-extinguishing units 33, 35, 37, are moved simultaneously to the open and closed-circuit positions by virtue of the fact that they form part of a movable, ladder-shaped structure 42 (FIG. including a pair of longitudinally extending insulating rods. 56 and transversely extending rungs or braces 57, to the center of which are secured the movable rod-shaped contacts 41. Actually, an end portion 41a (FIG. 3) of each rod-shaped movable contact 41 is tubular, as shown in broken lines in FIG. 3, to receive the end of the rod-shaped arcing contact 53, which is part of the stationary contact structure 39. The stationary main finger contacts 55 bear upon the outer surface of the movable rod-shaped contact '41 when the contacts are in the closed-circuit position. Each of the rods 56 (FIG. 2.) is slidably supported at its opposite ends Within two guide sleeves 59 and 61 that are attached to the two end castings 47 and 49, respectively (FIG. 2). An opening accelerating spring 63 is biased between a stationary spring plate 65 that is attached to the end casting 49 and a movable spring plate 67 that is supported between the movable insulating rods 56. The accelerating spring 63 is charged, or compressed, when the contacts are closed, and expands during the opening operation causing accelerating opening movement of the movable spring plate 67 and the movable operating rods 56 and movable contacts 55 to the open position, i.e. to the left as viewed in FIG. 2. A bumper 69, composed of alternate steel and rubber washers, is struck by the movable spring plate 67 during the opening operation providing a cushioned stop. The bumper 69 is supported by stationary support rods 71 that are attached to the end casting 49.

A conductor plate 72 attached to the end casting 49 and two of the stationary contact structures 39, all have rearwardly extending stationary split-finger contact assemblies 73 attached thereto (FIG. 3) with contact fingers 75, which bear on the outer surface of the associated movable contact rods 41. The cross-braces 57 move within split finger portions 77 of the contact assemblies 73.

The electrical circuit passing through each pole-unit extends through a conductor stud (not shown) passing through the terminal bushing 13, end support casting 49, conductor plate 72, stationary contact fingers 75, the first movable contact rod 4-1 and stationary contact fingers 55 of the first relatively stationary contact structure 39, and then in like manner, through the second and third serially related arc-extinguishing units 35 and 37, through the end casting 47 and through a conductor stud (not shown) i passing through the right-hand terminal bushing 12, as shown in FIG. 2.

In retrospect, the ladder-shaped movable contact assemblage 42 includes the two movable insulating operating rods 56, the three rungs or cross-braces 57 having the movable contacts 41 secured thereto at the central portions thereof, and the movable spring plate 67 (FIG. 2), which compresses, or charges the accelerating spring 63 when the parts are in the closed-circuit position shown in FIG. 2.

Referring to FIG. 2, it will be seen that clockwise rotation of the operating rod ll moves a crank-arm 73, which is attached thereto, in a corresponding clockwise direction, pulling a connecting rod 81 to the right and rotating a lever 83 in a counterclockwise direction about a stationarily mounted pivot pin 35. The pivot pin 85 is supported in a stationary bracket 87 that is welded, or otherwise attached to the outer side of the bumper .69. A connecting rod 89 is attached at one end to the lever 83, and at the other end to the movable spring plate 67, which is an integral part of the ladder-shaped movable contact assemblage 42. Counterclockwise rotation of the lever 83 moves the connecting rod 89 and the ladder-shaped movable contact asemblage 42 to the left, as viewed in 'FIG. 2, toward the open-circuit position (FIG. 3). The opening operation is accelerated by expansion of the compressed accelerating spring 63, which forces the spring plate 67 and, therefore, the movable contact assemblage 42 rapidly to the left. As was previously mentioned, the bumper 69 absorbs the shock of the opening operation and provides a cushioned stop at the end of the opening stroke.

Counterclockwise rotation of the operating rod 11 moves the crank-arm 79 in a corresponding counterclockwise direction, thereby thrusting the connecting rod 81 to the left to rotate the lever 83 clockwise about its stationary pivot 85. Clockwise rotation of the lever 33 moves the connecting rod 89 and the ladder-shaped movable contact assemblage 42 to the right to the closedcircuit position, as shown in FIG. 2. Closing movement of the movable contact assemblage charges the accelerating spring 63 between the stationary spring plate 65 and the movable spring plate 67.

An elongated high-pressure tank 7, containing fluid under high pressure, is supported beneath each of the three exhaust tanks 3 by three tubular-shaped blast valve casing 5. Each of the valve casings 5 has cylindricallyshaped mounting flanges 32 and 83 at the opposite ends thereof for enabling attachment by any suitable means, of the valve casings '5 to the high-pressure tank 7 and to the exhaust tank 3. Three insulating blast tubes 91 having cylindrical mounting flanges 92, are secured by any suitable means to the lower inside surface of the exhaust tank 3. Each of the blast tubes 91 is associated concentrically with one of the valve casings 5.

A blast valve 93 (FIG. 3) is operatively supported within each of the valve casings '5. A valve stem 95 of the blast valve 93 is pivotally supported on the outer free end of one arm 97 of a bell-crank 99. A valve-shaft portion @101 of the bell-crank 99 extends outside of the valve casing 5, and the free end of an external arm 103 of the bell crank 99 is pivotally attached to the blast-valve operating rod 14. As is illustrated in FIG. 2, a roller cam follower 107 is rotatably attached to a leg 109 of the blast valve operating rod M. A cam rod 111, having a projecting cam surface 113 thereon, is pivotally attached at its upper end to one end of a crank-arm 115, the other end of which is keyed to the operating shaft 111. The lower end of the cam rod 111 is slidably supported in a stationary guide sleeve 117, which is welded, or otherwise attached to one of the supporting flange plates 25 of the exhaust or interrupting tank 3.

It will be seen in FIG. 3 that there is an opening 119 provided in the exhaust tank 3 and also an opening 121 in the high-pressure tank 7 to allow passage of the blast fluid when the blast valve 93 is in the open position.

Referring to FIG. 2, it will be seen that clockwise rotation of the operating shaft 11 moves the crank arm 115 clockwise forcing the cam rod 111 downwards. As the cam rod 111 moves down, the cam surface 113 thereof engages the roller, or cam follower 107 moving the blastv alve operating rod 14 to the right and consequently rotating the blast-valve bell cranks 99 (FIG. 3) clock-wise to open the blast valves 93. As the blast-valve operating rod 14 moves to the right, the right-hand end thereof slides within a chamber 123, that is welded, or otherwise attached to one of the flange plates 25, and charges a compression spring (not shown) disposed within the chamber 123 As the cam rod 111 reaches its lowermost position, the cam follower 107 rides off of the upper end of the cam surface 113, thereby allowing the blast-valve operating rod 14 to return to the valve-closed position under the bias of the retracting compression spring, that is disposed within the spring chamber 123. The blastvalve operating rod .14 will open and close the blast valves 93 in the same manner when the operating shaft 11 is rotated counterclockwise back to the closed-circuit position shown in FIG. 2. This movement raises the cam rod 111 causing the cam follower 107 to ride over the cam surface .113 to momentarily open the blast valves @3 during the closing operation. This has the beneficial effect of preventing prestriking during the closing stroke as the several contact structures near engaging position. By a suitable collapsible linkage, however, such blast-valve opening during the closing stroke could be eliminated.

Referring now to FIGS. 3, 4 and 5, one of the arcsplitter boxes 43 is associated with each of the arc-extinguishing units 33, 35 and 37. Each of the arc-splitter boxes 43 comprises two support members 1 25, each of which is attached to the inside of one of the stationary insulating support rods 45. Three are splitter plates 127 fit within slots in complementary faces of the support members 125- to form a flaring-type arc-interrupting structure (FIG. 3). Each of the plates 127 has a tunnel opening or notch 1129 provided therein to allow passage of the movable contact rod '41 therethrough.

The pole-unit A is shown in FIG. 2 in the closedcircuit position. It will be noted that the crank-arm 79, for operating the movable contact assemblage 42, and the crank-arm 115, for operating the blast-valve operating rod 13, are both rigidly keyed to the operating shaft 11, and they, therefore, function as a bell-crank upon rotation of the operating shaft 11. Clockwise rotation of the operating shaft 11, therefore, causes simultaneous opening movement of the three movable contact rods 41, and, at the same time, simultaneous opening movement of the three blast valves 39, causing thereby a separate blast of fluid to flow upwardly from the high-pressure tank 7, through each valve casing 5, through each blast tube 91, and against an arc 44 established between each of the opening sets of separable contacts 53, 55 and 41; forcing the arcs to move into the arc-splitter boxes 43 to be broken up and extinguished between the diverging splitter plates 127 as shown in FIG. 7.

It will be noted that a blast of gas will be directed at each of the closing contacts 53, 55 and 41 during a closing operation. This prevents pre-striking of an are between the closing contacts, as mentioned above. The operating shaft 11 moves within the weatherproof tube 9 (FIG. 1) to simultaneously operate the three-pole units A, B and C of the circuit interrupter 1.

The arc-extinguishing fluid may be air or any suitable gas, but is preferably sulfur hexafiuoride (SF or selenium hexafiuoride (Sel which gases are extremely stable and inert .giving excellent results.

Preferably, the pressure within the high-pressure storage tank 7 is sufficient to produce an adequate blast pressure to force the arcs 44 between the arc-splitter plates 127. For example, a pressure of 200-250 p.s.i. may be employed, although higher or lower pressures may be satisfactory for other applications. The exhaust pressure within the interrupting tank 3 may, for example, be 30-45 p.s.i., when sulfur hexafiuoride is employed as the extinguishing gas. Where air is used as the extinguishing medium, the tanks 3 may be suitably vented to the atmosphere.

When an expensive gas is used, such as sulfur hexafiuoride, it is desirable to reclaim the gas and recompress it, as described in the aforesaid Yeckley et al. application.

From the foregoing description, it will be apparent that there is provided an improved gas-blast type of structure in which accurate control and effective direction of the gas blasts are obtained. The high-pressure tank 7, being at ground potential is easy and safe to service. There is no necessity for tubing to carry gas from ground potential to a high-potential gas reservoir chamber, as was the case in the foregoing application. For high kva. ratings a highly eifective gas, such as sulfur hexafluoride may be employed, whereas for the lower kva. ratings, compressed air may be employed. Highly accurate adjustment and control of the blast jets may be easily obtained with the disclosed structure.

Although there has been illustrated and described a specific interrupting structure, it is to be clearly tinderstood that the same was merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the invention.

I claim as my invention:

1. A fluid-blast circuit interrupter comprising, in combination, an exhaust tank, an elongated arc-extinguishing assemblage supported within said exhaust tank, said arcextinguishing assemblage including a plurality of serially related arc-extinguishing units, each of said arc-extinguishing units comprising arc-splitter means for breaking up an arc to effect extinction of the arc, means for simultaneously drawing a plurality of serially related arcs along the assemblage one within each arc-extinguishing unit, a source of high-pressure gas, a separate blast valve associated with each arc-extinguishing unit and operable to direct a blast of gas crosswise toward the are established within that unit to force the are into the associated arc-splitter means, and means for effecting simultaneous actuation of the blast valves.

2. A fiuid-blast circuit interrupter including a pair of terminal bushings supported in spaced relationship, an elongated arc-extinguishing assemblage supported by said terminal bushings and conductively bridging said terminal bushings, said arc-extinguishing assemblage including a plurality of serially related arc-extinguishing units, means for drawing a plurality of elongated serially related arcs along the assemblage one within each arc-extinguishing unit, a source of high-pressure gas, a separate blast valve associated with each arc-extinguishing unit and operable to direct a blast of gas crosswise toward the arc established within that unit, and means for effecting simultaneous actuation of the blast valves.

3. A circuit interrupter including, in combination, a generally elongated exhaust tank, a pair of spaced terminal bushings extending interiorly within said exhaust tank, a generally elongated arc-extinguishing assemblage supported from the interior ends of said pair of terminal bushings and positioned in a generally concentric relation to said exhaust tank, said arc-extinguishing assemblage including a plurality of serially related arc-extinguishing units, means for drawing a plurality of serially related elongated arcs along the assemblage one within each arcextinguishing unit, a source of high pressure gas, a separate blast valve associated with each arc-extinguishing unity and operable to direct a blast of gas toward the associated arc in a direction generally normal to the direction of the length of the associated arc, and means for effecting simultaneous actuation of the blast valves.

4. A circuit interrupter including, in combination, a generally elongated exhaust tank, a pair of spaced terminal bushings extending interiorly within said exhaust tank, a generally elongated arc-extinguishing assemblage supported from the interior ends of said pair of terminal bushings and positioned in a generally concentric relation to said exhaust tank, said arc-extinguishing assemblage including a plurality of serially related arc-extinguishing units, means for drawing a plurality of serially related elongated arcs along the assemblage one within each arc-extinguishing unit, a source of high pressure gas, a separate blast valve associated with each arc-extinguishing unit and operable to direct a blast of gas crosswise toward the are established within that unit, a separate blast tube associated with each of said blast valves, said blast tubes extending upwardly within said exhaust tank to direct said fluid blasts into said arcs, and means for effecting simultaneous actuation of said blast valves.

5. A circuit interrupter including a grounded generally elongated exhaust tank, a pair of upstanding terminal bushings extending interiorly within said exhaust tank adjacent opposite ends of said exhaust tank, an arcextinguishing assemblage supported by the interior ends of said terminal bushings and conductively bridging them, said arc-extinguishing assemblage including a plurality of serially related arc-extinguishing units, an externally disposed high-pressure tank at ground potential and containing a supply of gas under high pressure, a plurality of conduits extending between said high-pressure tank and said exhaust tank, each of said conduits directing a blast of gas at one of said arc-extinguishing units, a separate blast valve associated with each of said conduits, and means for simultaneously actuating all of said blast valves.

6. A fluid-blast circuit interrupter including a grounded generally elongated exhaust tank, a pair of spaced terminal bushings extending interiorly within said exhaust tank, a generally elongated arc-extinguishing assemblage extending between and bridging the spaced interior ends of said spaced terminal bushings, the arc-extinguishing assemblage including a plurality of serially related arc-extinguishing units, a grounded generally elongated high-pressure tank disposed adjacent said generally elongated exhaust tank and extending lengthwise in the same direction as said exhaust tank, said high-pressure tank containing fluid under high pressure, a plurality of valve casings extending between said high pressure tank and said exhaust tank, each of said plurality of valve casings directing a blast of fluid at one of said arc-extinguishing units, a separate blast valve associated with each of said valve casings and means for simultaneously actuating all of said blast valves.

7. A circuit interrupter including, in combination, a generally elongated exhaust tank at ground potential, a pair of spaced terminal bushings extending generally upwardly out of said generally elongated exhaust tank adjacent opposite ends thereof, a generally elongated arcextinguishing assemblage supported from the interior ends of said spaced pair of terminal bushings, said arc-extinguishing assemblage including a plurality of serially related arc-extinguishing units of the cross-blast type, a highpressure tank containing high-pressure fluid and supported adjacent said generally elongated exhaust tank, said high pressure tank being at ground potential, a separate blast valve associated with each of said arc-extinguishing units and operable to direct a blast of gas toward the arc established within that unit, and means for simultaneously actuating all of said blast valves.

8. The combination in a fluid-blast circuit interrupter of a generally elongated exhaust tank :at ground potential, a pair of spaced terminal bushings extending interiorly within said exhaust tank adjacent opposite ends thereof, an arc-extinguishing assemblage supported by the interior ends of said terminal bushings and conductively bridging them, said arc-extinguishing assemblage including a plurality of serially related arc-extinguishing units, a grounded high-pressure tank disposed adjacent said exhaust tank and containing fluid under high pressure, a conduit extending between said high-pressure tank and said exhaust tank adjacent each of said arc-extinguishing units, a separate blast valve associated with each of said conduits, means for simultaneously actuating all of said blast valves, a separate insulating blast tube disposed within said exhaust tank between each of said conduits and its complementary arc-extinguishing unit, and said 'blast tubes cooperating with said conduits to direct a blast of fluid at each of said arc-extinguishing units upon the simultaneous actuation of said blast valves.

9. The combination in a fluid-blast circuit interrupter of a generally elongated exhaust tank at ground potential, a pair of spaced terminal bushings extending interiorly within said exhaust tank adjacent opposite ends thereof, a plurality of serially related sets of contacts supported by the interior ends of said terminal bushings, each of said sets comprising a stationary contact and a movable contact cooperable with said stationary contact to open and close said contacts, each of said sets of contacts upon opening establishing an arc, arc splitter means supported near each of said sets of contacts to break up said arcs, a high pressure tank at ground potential disposed adjacent said exhaust tank and containing a supply of fluid under high pressure, a blast-valve casing complementary with each of said sets of contacts, said blast-valve casings being positioned between said high pressure tank and said exhaust tank, a blast valve associated with each of said blast-valve casings, blast valve opening means for simultaneously opening all of said blast valves, contact opening means for simultaneously opening all of said sets of contacts whereby an arc is established at each of said opening sets of contacts, and means for simultaneously actuating said blast valve opening means and said contact opening means to simultaneously direct a separate blast of fluid at each of said arcs.

10. A circuit interrupter including, in combination, a generally elongated exhaust tank at ground potential, 21 pair of spaced terminal bushings extending generally upwardly out of said exhaust tank, a plurality of serially related sets of contacts supported by the interior ends of 'said terminal bushings, each of said sets comprising a stationary contact and a movable contact cooperating with said stationary contact to open and close said contacts, means mechanically connecting said movable contacts as a unitary movable contact structure, a high pressure tank at ground potential containing a supply of high pressure fluid and being disposed adjacent said exhaust tank, a valve housing complementary with each of said sets of contacts, a blast valve associated with each of said valve housings, said valve housings being positioned between said high pressure tank and said exhaust tank, means operable to simultaneously open all of said blast valves and at the same time to move said unitary movable contact structure to simultaneously open all of said sets of contacts, whereby simultaneously a separate blast of gas is directed at each of said opening sets of contacts.

11. A gas blast circuit interrupter including, in combination, a generally elongated exhaust tank at ground potential, a pair of spaced terminal bushings extending generally upwardly out of said exhaust tank, a plurality of serially related sets of contacts supported by the interior ends of said terminal bushings, each of said sets comprising a stationary contact and a movable contact cooperable with said stationary contact to open and close said contacts, each of said sets of contacts upon opening establishing an arc, arc splitter means disposed near each of said sets of contacts to break up said arcs, a high pressure tank at ground potential disposed adjacent said exhaust tank and containing a supply of gas under high pressure, a valve-housing complementary with each of said sets of contacts, said valve-housings being disposed between said high pressure tank and said exhaust tank, a separate blast tube disposed within said exhaust tank between each of said valve-housings and its complementary set of contacts, a separate blast valve associated with each of said valve-housings, blast valve opening means for simultaneously opening all of said blast valves, contact opening means for simultaneously opening all of said sets of contacts to thereby simultaneously establish an are at each of said sets of contacts, means for simultaneously actuating said blast valve opening means and said contact opening means to simultaneously direct a separate blast of gas through each of said blast-tubes forcing each of said arcs into its associated arc splitter means.

12. A gas blast circuit interrupter including, in combination, a generally elongated exhaust tank at ground potential, a pair of spaced terminal bushings extending generally upwardly out of said exhaust tank, three serially related sets of contacts supported by the interior ends of said terminal bushings, each of said sets comprising a stationary contact and a movable contact cooperating with said stationary contact to open and close said contacts, means mechanically connecting said movable contacts as a unitary movable contact structure, contact opening means operable to move said unitary movable contact structure to simultaneously open all of said sets of contacts, each of said three sets of contacts upon opening establishing an arc, arc splitter means supported near each of said three sets of contacts to break up said arcs, a grounded generally elongated high-pressure tank disposed adjacent said generally elongated exhaust tank and extending lengthwise in the same direction as said exhaust tank, said high-pressure tank containing gas under high pressure, a valve-casing complementary with each of said three sets of contacts, said valve-casings being disposed between said high pressure tank and said exhaust tank, a separate insulating blast tube disposed within said exhaust tank between each of said valve-casings and its complementary set of contacts, a separate blast valve associated with each of said valve casings, blast valve opening means for simultaneously opening all three of said blast valves, means for simultaneously actuating said blast valve opening means and said contact opening means to simultaneously direct a separate blast of gas through each of said blast tubes, and said blasts forcing said arcs into said are splitter means.

13. A circuit breaker comprising, in combination, an exhaust tank, a pair of spaced terminal bushings extending interiorly within said exhaust tank, an arc-extinguishing assemblage supported from the interior ends of said terminal bushings, said arc-extinguishing assemblage comprising a plurality of stationary contacts, a unitary movable contact structure comprising a plurality of movable contacts each of which is cooperable with one of said stationary contacts to establish an are, means operable to move said unitary movable contact structure to simultaneously establish a plurality of arcs one at each of the sets of cooperable contacts, arc-splitter means supported in proximity to each of said sets of cooperable contacts, a source of high-pressure gas, a separate blast valve associated with each of the sets of cooperable contacts and operable to direct a blast of gas toward the arc established at the associated set of contacts to force the are into the associated arc-splitter means, and means for efiecting simultaneous actuation of said blast valves to thereby extinguish all of said arcs.

References Cited in the file of this patent UNITED STATES PATENTS 2,155,263 Flursheim Apr. 18, 1939 2,390,966 Scott Dec. 11, 1945 2,824,937 Strom Feb. 25, 1958 FOREIGN PATENTS 539,236 Great Britain Sept. 2, 1941 626,842 Great Britain July 21, 1949 Ll3,342 Germany Nov. 22, 1956 

1. A FLUID-BLAST CIRCUIT INTERRUPTER COMPRISING, IN COMBINATION, AN EXHAUST TANK, AN ELONGATED ARC-EXTINGUISHING ASSEMBLAGE SUPPORTED WITHIN SAID EXHAUST TANK, SAID ARCEXTINGUISHING ASSEMBLAGE INCLUDING A PLURALITY OF SERIALLY RELATED ARC-EXTINGUISHING UNITS, EACH OF SAID ARC-EXTINGUISHING UNITS COMPRISING ARC-SPLITTER MEANS FOR BREAKING UP AN ARC TO EFFECT EXTINCTION OF THE ARC, MEANS FOR SIMULTANEOUSLY DRAWING A PLURALITY OF SERIALLY RELATED ARCS ALONG THE ASSEMBLAGE ONE WITHIN EACH ARC-EXTINGUISHING UNIT, A SOURCE OF HIGH-PRESSURE GAS, A SEPARATE BLAST VALVE ASSOCIATED WITH EACH ARC-EXTINGUISHING UNIT AND OPERABLE TO DIRECT A BLAST OF GAS CROSSWISE TOWARD THE ARC ESTABLISHED WITHIN THAT UNIT TO FORCE THE ARC INTO THE ASSOCIATED ARC-SPLITTER MEANS, AND MEANS FOR EFFECTING SIMULTANEOUS ACTUATION OF THE BLAST VALVES. 